IN THE classic Orson Welles film “Citizen Kane,” a reporter, attempting to discover the essence of the protagonist, works backwards by trying to unravel the meaning of his final utterance, “Rosebud.” In trying to uncover the essence of Mike Hampton a reporter would be served by using the reverse method, for in Hampton’s very first words one discovers the spirit of one of the games fiercest competitors.

“It wasn’t Mommy or Daddy,” Mike Hampton Sr. recalled of his son’s first words a quarter of a century ago. “The first word he ever said was ‘Ball.'”

In the years since then Hampton has been using a ball to become one of the game’s best pitchers. He has a lot more talking to do in his life, much of it with a baseball, and the Mets are now looking forward to him doing it on their behalf following the blockbuster deal last month that brought the 27-year-old lefty to Shea in exchange for Octavio Dotel and Roger Cedeno.

When discussing Hampton, those most familiar with the Mets new ace use words like “competitor,” and “competitive” over and again. Hampton seems to thrive on competition, harnessing its driving force and using it to take him to the heights he reached last season when he went 22-4 for the Astros and was the runner-up in the Cy Young Award voting.

In Hampton the Mets have not only acquired a complete all-around player — this year’s Silver Slugger winner for pitchers, he was scouted by the Orioles to be a centerfielder — they have a pitcher who was raised from infancy to play sports, compete and win.

Walking at eight months, promoted as a kindergartner to play with third graders because his classmates couldn’t catch balls he threw, and constantly pushed by his father to excel, Hampton’s path to baseball stardom began early.

“All the athleticism came so easily for him, but he also worked at it all the time too,” said Mike Hampton Sr., who runs the family’s 38-year-old shell-fishing company in Crystal River, Fla. “I was tough on him. I knew no one would treat him with kid gloves, so I treated him with boxing gloves. He’s told me he’s seen how that helped him when he got to the majors.”

Sports was the No. 1 activity in the Hampton household and virtually every family vacation was spent at baseball tournaments around Florida. Although he also excelled as a defensive back in football, it was clear as early as junior high that baseball would be his ultimate goal, at least until someone showed him he couldn’t make it. No one ever did.

When Mike broke his right wrist playing football as a high school freshman, his mother Joan was relieved it wasn’t the other hand.

“I said ‘Thank God,’ when the doctors told me and people thought I was happy he broke his wrist,” Joan said. “I was just happy it wasn’t his pitching arm.”

Besides a relentless dedication and a readiness to take instruction, Mike also had that competitive edge. In junior high he ran track. In a meet with three other schools he finished fourth and last in the hurdles. So he went to work and the next week finished third. He continued to work and two weeks later, against the same boys, he won the race.

“If you beat him today,” his father said, “you better be ready for him tomorrow because he’ll come back at you.”

Later in high school Mike wrestled but was not great at it — probably because there was no ball involved. Mike knew he was destined to give up wrestling, but before he quit he improved considerably and scored several pins. Only then, after he showed he could win, did he move on from that sport.

Eventually it came down to football and baseball. Football scouts from all the southern schools and one from Notre Dame came around but before any of them offered a scholarship Hampton made it clear that baseball was his future, a decision welcomed by his high school baseball coach, Joe Buccheri.

A Flushing, Queens, native and a bat boy for Joe Torre’s St. Francis Prep team in Brooklyn, Buccheri took over a struggling Crystal River baseball program in 1985 and met the young Hampton two years later. Hampton would almost singlehandedly turn the program around, taking it to heights it had never before seen.

By the time Mike was a senior the scouts followed him like groupies, raising and dropping their radar guns whenever he unloaded an 89-mph fastball. Hampton wasn’t initially invited to the 1990 Florida All-Star Game, but got the call when Chipper Jones broke his hand. After an impressive first game, all the scouts wanted to know when they would see him again.

Said Hampton’s high school catcher Brian Fitzgerald, “I’ll get cancer of the back from all those radar guns.”

Mike was eventually drafted by the Mariners in the sixth round in 1990 and didn’t get a very high signing bonus. His father wanted to hold out for more money, but the anxious 17-year-old just wanted to sign and start pitching.

“I’ll make the money later,” he told his father, and next year as a free agent Hampton could sign for as much as $100 million.

After signing, Hampton went to the Mariners rookie ball team in Arizona and it was there he was faced with a team full of Mike Hamptons, promising young players who were all the stars of their county or state. That only heated his competitive blood.

“I’ll just have to out-work them,” Hampton told Buccheri on the phone, “Because I’m going to finish first.”

Indeed he did. Hampton soared through the Mariners minor league system and earned a spot on the major league team in 1993, and at 20 becoming the youngest player in the American League at the time. But pitching for Lou Piniella is never easy and Hampton was quickly sent back to the minors, marking the first backwards step in his sporting life.

The Mariners may have given up on him, but Astros GM Bob Watson, who had seen him pitch in the Puerto Rican winter league, grabbed him in a trade for Eric Anthony, who is now out of baseball.

“The one thing I loved about him,” Watson said the other day from Houston, “is he was a tremendous competitor. God Almighty, what a competitor.”

In Houston, Hampton hooked up with Mel Stottlemyre, now the Yankee pitching coach, and blossomed under his tutelage. “He taught him the mental part of the game,” Mike Sr. said. “He needed that.”

Through six years in Houston Hampton became an immensely popular player, especially with his teammates and became one of the best lefthanders in the game.

The Mets have found this out over the years. Since 1997 Hampton was 4-0 against them with a 1.33 ERA. Now, instead of suffering at his hand, they will enjoy his talents and his competitive drive every time they hand him the ball.